The pollengrains are formed by meiotic division.
Pollen grains or the male gametes are formed in higher group of plants or which are termed as Spermatophytes i.e Gymnosperms and Angiosperms. And pollen grains (male gametes) and egg(female gamete) are formed by reductional or Meiotic division, since the union of both gametes must get back to the original ploidy level.